   commentLine("1，调用fmt.println(f2)")
    fmt.Println(f2())
    commentLine("1.7，上述打印的值为a2")

    commentLine("2-> 压栈 test1, 1st, 2nd")
    defer test1()
    defer fmt.Println("1st defer")
    defer fmt.Println("2nd defer")

    commentLine("2 <- 出栈 2nd,1st,test1()->")